Method of forming drawbar yokes



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4 Sheets-Sheet 3 F Ei H. P. ORR

METHOD FORMING DRAWBAR YOKES Filed Feb. 24, 1922 FI EJD.

Feb. 5.!

Petented Feb. 5, 1924.

nnar arnar HERBERT Pi ORR, OF INDIANA, PENNSYLVANIA, ASSIGNOR OF ONE-FGURTH TO HEN- DERSON B. DOUGLAS, OF PITTSBURGH, PENNSYLVANIA, .AND ONE-FOURTH TO AN DR-EW CHRISTIANSON, OF BUTLEE, PENNSYLVANIA. I

METHOID OF FORMING DRAl/VBAR YOKES.

Application filed February 24, 1922. Serial N'O. .539,018.

TO all whom Z'Zf may COnern:

Be it known that I, Hnmmn'r P. ORR, a subject of the King of Great Britain, and a resident of Indiana, in the county of Indiana and State of Pennsylvania, have invented' a new and use'ful Improvement in Methods of Forming Drawbar Yokes, of Which the following is a Specification.

This invention relates to a method or process of making draft gear yokes or draw bar yokes, and the object of the invention is to provide an inexpensive and expeditious method of manufacturing yokes of a single piece without seams or joints. It is also an object to make such yokes by a orging process to obviate the difiiculties of casting and to secure a product free from the dsadvantages incident to those Which are formed by casting. It is a further object to form the Completed yoke by die orging in which the minimum number of steps or separate Operations is necessary.

According to the present invention a billet is pierced, upset and extruded in one set of dies so as to form the head of the yoke, and this partially formed yoke is then subjected to a further extruding operation in another set of dies to elongate the strap portions and complete the yoke.

The invention will be more readily understood from the following description taken in connection with the appended claims.

The method can be described most readily by reference to the die sets used in performing the same, and will, therefore, be set forth in Connection with a description of the tWo separate and independent die sets employed for Carrying out the steps of the process.

In the accompanying drawings Fig. l is a transverse sectional View taken on the line I of Fig. 2: Fig. 2 a Vertical transverse sectional View through the die mechanism. employed for Carrying out the first step of the process, showing' the billet in the die and the plunger in its raised position; Fig'. 3 a tragmentary Vertical sectional View taken in a plane at right angles' to that of Fig. 2; Fig. 4: a frag'mentary Vertical transverse sectional View showing the transformation of the billet and the relative position of the parts at the completion of the first step of the forging operation; Fig. 5 a View similar to Fig. l taken in a plane at right angles to said figure; Fig. 6 an elevational View of the partially formed yoke as it appears at the end of the first forging process; Fig. 7 a view similar to Fig. 6 taken in a plane at right angles thereto 8 a Vertical transverse sectional View with parts in elevation of the die mechanism employed for Carrying out the second step of the forging Operation. showing the partiall formed yoke within the die and the position of the parts before the descent of the extrusionplunger; Fig. 9 a fragmentary View of the parts illustrated in Fig. 8 showing the relative position of the parts after the plunger has reached its lowermost position to complete the formation of the yoke; Fig. 10 a. transverse sectional view taken on the line X X of Fig. 8; Fig. 11 a view similar to Fig. 9 taken in a plane at right angles thereto; Fig. 12 an elevational View showing' the finished yoke after the completion of the forginp; Operations, and Fig. 13 a similar view taken in a plane at right angles to that of Fig. 12.

Two separate sets of dies are used in Carrying out the method or process, the first set being illustrated in Fig's. 1 to 5 and the second set in Figs. 8 to 11. ln order to clarit'y the showing of the several figures, illustration of the several bolts employed for binding the parts together has been omitted from some O'f the drawings. A

The :female member of the first set of dies is mounted in a die holder l which is preferably circular in Cross section having a substantially rectangular recess 2 at its center in which the severa sections comprising the composite die member are rctained and held in position between looking wedges 3 and 4 respectively, the bottom ol* the recess' being closed by a base plate 5 bolted to the holder 1..

The 'female die Comprises an upper section 6 and lower section 7, each ot which is split throughout its entire height to torm correspondingfily shaped sulrsections. those of the upper section 6 being' shown at S and 9 in Figz. l, which are bound against the sides ot' interlockingz wear strips 10 and ll extending the 'full height of the die, all of said parts being: bound together to 'form a unit by means otspaced bolts indicated at 12.

The Conformation of the surt'ace o't' the central recess in the upper section corresponds to that of the exterior lateral surtace of the jaw portions 13 of the formed yoke,

and the re'cess formed between the Cooperat which the lower end of the plunger 16 pro-' jects during its downward movement for a purpose to be presently described.

Plunger 16 is rectangular in cross section,

having its body portion of such dimensions as to fill the-opening ol' the die as clearly shown in Figs. 4 and 5. The lower extremity is' .cut 'away in the manner illustrated by Figs, 2 and 3 leaving overhanging ledges 17 and 1 8 having a curvature Corresponding to the edgesi 19 of the jaws 13, and providing a nose of tapered form. p The cavity of thedie, as viewedin Fg. 3, is of uniform width throughout its extent andiequals that of the corresponding dimension of 'the body of plunger IG. Thec'avity, however, as viewed in a plane at right angles thereto, see Fig 2, conforms tothe shape of the jaws 13 throughout the upper section 6, and is of the same Width as that of the nose of the plunger throughout the extent of the enlarged portions l l and 15, below which it is substantiallv the same widthas the strap portions 20 of the finished yoke.

Slidably mounted for reciprocating movement in a duct leading from the bottom of the die cavity through the several parts is an eX- traction or kick-out plunger 21, the head 22 of Which lies flush with the floor of the cavity. This plunger extends through the base plate 5, is normally urged towards its lowermost position, and is adapted to be moved upwardly to ejectthe partially formed yoke after the first step of the forging operation has beencompleted. Reciprocation thereof may be caused by any well known means suchas a hydraulic pressuro cylinder not shown.

The operation of the step performed in this first die set is as follows: A billet (6 of metal heated to the proper temperature is placed in the die cavity, as shown in Figs; 1 to 3, and pressure applied to plunger 16. As the plunger descends it pierces the billet spreadng a part of the metal into contactw-ith the wall of the upper section 6, forcing a portion of it downwardly into the cavity of the lower section 7 and extruding a portion upwardly around the nose of the plunge'r, bringing it into position to be contacted hy the ledges'17 18 as the plunger continues to descend. After the nose of the pl finger has completely pierced the billet .it enters: the en'large1nents1-14 -'15 of the cavity in the 'lower section 7,* as shown in Fig. l, efl'ecting a shearing action at the points 23 and'2'3' and thus 'separates the jawsl' from the strap portions 20 'of the partially formed yoke, and* atfth'e :same time' shapes' the edges' 19 by Confinement of the inetal below the ledges 17 and 18.

Figs. 4 and 5 shows the plunger after it has reached its limit of downward movemont and has oompleted the first step in-the forging operation. In such operation,-the billet (L has been shaped into a partially formed draw bar yoke, the jaws 13 of Which have been forced to' assume their final shape, and which jaws are connected by short strap portions 2-l to a thic'k end portion Z).

In actual practice, it is foundthat during the movement of the plunger into the enlargements let 15 ell'ecting the piercing action above referred to *and the ninitial 'formation of the strapportions 24: adjacent the jaws of the yoke, a *small quantity of metal will be forced ahead of the plunger nose resulting' in the formation of a= narrow rib or bead C at the juncture of the members 24: and the'end portions b. n The partially formed yoke as it appears after treatment in the first set of dies s illustrated in Figs. 6 and 7, and is ejected in this form by reciprocation of the knick-out plunger 21 after the plunger 16 hasbeen raised.

The die set' for completing'the formation of the yoko will' now be described, The female part of this set isalso composed of a number of parts comprising the complete structure and is. similar' to the first set in having a base plate,. die holder, looking wedges and an ejection .plungerwhich,-therefore, need not be particularly described.

The die propercomprises themembers 30, 30', 31, 131' and a U.-shaped wea'rme1nber32 having the upper limbs 33,- 33', all of which are bolted together as a un it similarly tothe method employed in thefirst die set. 'Mounted for reciprocation .in suitably formed guide ways and disposed adjacent the die' cavity is a pair of .cutter blocks 34, '34' provided With sh-earing orcuttingedges 35, att-heil' upper ends, and are so formed as to center the plunger 36 which is provided with a slightly. reduced extremity 37 corresponding in width 'to the space between the bodies of the cutting blocks 34. 34' into which the metal Z) is to* beforced. The blocks 34 34' are inounted upon rods 38, 385 yieldingly urged to the, positionshown in Fig. 8 by any suitable .u1eans, notshown-,n so as to permit their moving bodily 1 down wardly after 'the pliuiger has movedsufliciently to posi'tivolv contact the same.

As clearly shown in Figs. 8 to 11, the Cross sectional-shape of the plunger. 36 is rectangw lar throughout -its length, fitting between the cutting edges 35, 35'- at the upper. ends.

of the blocks 345, 34' andspaoed.fronreach of* the limbs ;33, 3 3'fof the -internediate w'ear' member 32 a distance equal to the thickness of .the 'strap portions 20. v

The operation of; the ,second t 'set' ofFClies and' 'sthe changes prodaeed* thereb are as ill follows: The partially formed yoke in the form it leaves' the first die set, as illustrated in Figs. 6 and 7, is placed in the positio-n shown in Fig. 8 and the end 37 of the plunger 36 brought into contact with the upper surface of the thickened portion b, the body of the plunger filling the opening between the jaws 13 and the short strap portions 24. When pressure is applied to the plunger the partially formed yoke is brought home in the die, shearing or cutting off the ribs c by means of the cuttng ed es 35, 35, the yielding supporting means Or the blocks 34, 34' offering sufiicient resistance to assure such action. As soon as the enlarged section of the plunger firmly contacts the blocks 34, 34, however, they are forced bodily downwardly, the p-lunger and blocks moving together as a unit, bringing the bottom surface of the thickened portion Z) into Contact with the floor of the die cavity, while continued downward movement of the plunger extrudes the metal of the part b around the opposite sides of'the plunger through the space provided between the plunger and the limbs 33, 33', causing the elongation of the strap portions of the yoke. This extruding action is continued until the end portion 39 connecting the straps 20 is reduced to about the same thickness as the straps, the several parts assuming the positions shown in Fig. 9. During this extrusion of the metal of the part b, jaws 13, previously formed, gradually slide upwardly along the sides of the plunger which functions as an internal guide. The completely formed draw bar yoke is then ejected after withdrawal of the plunger by 'actuation of the ejection or kick-out device in identically the same manner as previously described in Connection with the first die set.

The completely formed forging as it leaves the second die set, as illustrated in Figs. 12 and 13, can be subjected to any further finishing steps that are found to be desirable, such as punching Operations for forming apertures for pins or other similar devices.

It is thus seen that the yoke is completely forged in but two steps in the first of which the head or jaw portions are formed, and in the second of which the straps and connecting end portions are produced, and. that a product is secured containing the customarv open spaces between the head, strap and connecting end portions, thus obviating the necessity of additional steps to produce such Spaces after the completion of the forging operation.

I claim:

1. A method of ferming draw bar yokes which comprises for'cing a plunger entirely through a billet to form a hollow head with a substantially even surfaced Opening eX- tending completely. through the head, and subsequently subjecting the ,end opposite the head so formed to extrusion to produce side straps thereon.

2. A method of making draw bar yokes which comprises the subjection of a billet to pressure between a plunger and die, forcing the plunger entirely through the billet to form a hollow head, with a thickened end portion and straps therebetween whereby all fins formed by the metal in advance of the plunger will project laterally outwards and be disposed upon the exterior surface of the said thickened end portion, and subsequently subjecting the partially formed yoke to pressure between a second plunger and second die extruding the metal of the thickened end portion to elongate aid straps and shearing ofl' said external 3. A method of forging draw bar yokes which consists in subjecting a solid blank to pressure between a plunger and die to force the plunger completely through the blank to form a hollow head having a substantially smooth opening extending completely through the head and outwardly flared jaws at one extremity and a thickened portion spaced therefrom at the other, and subsequently extruding the metal of the said thickened portion to form elongated side straps thereon.

4. A method of making draw bar yokes which consists in subjecting a solid billet to pressure between a plunger and die to force the plunger completely through the billet and extrude the metal thereof to form v a hollow head at one end having a Substantially even-surfaced opening extending entirely through the head and a thickened portion at the other and straps therebetween, and then extruding the metal of the thickened portion to elongate said straps.

5. A method of making draw bar yokes which comprises the subjection of a billet to pressure between a plunger and die to force the plunger entirely through the billet, simultaneously piercing, upsetting and extruding the metal thereof to form a hollow head having a substantially smooth opening extending completely through the head with side straps and a' thickened portion connecting the extremities of the side straps, and subsequently extruding the metal of the thickened portion to elongate said straps.

In testimony whereof, I sign my name.

HERBERT P. ORR. Witnesses:

J. W. BARNEY, J. W. HOOVER. 

